Is the PCI card much different from the keyboard synth itself? Why is this PCI card so special? I didn't find but a single demo of it online. Hmm.
the better way to think of it is as a 90s product. the later OASYS keyboard was a linux-based workstation which did not have much in common with the earlier stuff and was closer in line to the M3 and Radias products.
In the 90s, Korg spent a ton of money on R&D for the OASYS project, and ended up with a super beast system that was so expensive no one but the top tier pros could afford it (something like $15K in 1994 dollars) so Korg took all the technology from the OASYS project and split it up into individual components and rode that cash cow off into the sunset. Most of Korg's 90s products were derived from it.
Trinity/Triton synth derivatives = ACCESS/HI synthesis engine, Sampler functions, ROMpler functions, sequencing.
Prophecy/Z1/E(x)-1, MS2000s = the Z1 and Prophecy have the full MOSS system for physical modelling, the E(x) and MS2k boxes only used the analog modelling components
WaveDrum = another subset of the physical modelling tech purely for percussion
1212IO, other IO products = effects and IO from the OASYS project, split off into standalone IO and effects products
its an incredible piece of tech for the time, and unbelievably tedious to work with, but the sonic results are well worth it. it never got ported over to OSX or even to windows XP i believe, so its kind of become abandonware for the most part. If they had made an OSX version and put serious work into the interface (and its MIDI implementation, mighty christ is it awful) it could have been an amazing product.